Experiments with a New Message Format for Digital Representation of Photographs.
Abstract
Ordinarily, a black-and-white photograph is digitally encoded in the PCM format; the picture is dissected into L square samples and the brightness of each sample is represented by a binary number of k bits. Consequently, the picture message contains k(L square) bits, including L square most-significant and exactly L square of each subsequent significance rank. With the aid of a digital computer and special picture/magnetic-tape inter-conversion equipment, experiments were performed to evaluate a radically different structure for the picture message. In effect, a k(L square)-bits message in the experimental format includes more than L square bits of some, more important, significance ranks and less than L square of other, less important, ranks. The number of brightness levels remains 2 to the k power. Pictures decoded from the experimental format were compared with pictures reconstructed from PCM-format messages having the same or larger number of bits. They seem to indicate that a well-chosen embodiment of the experimental format offers better quality than PCM under the constraints of fixed message length and fixed number of brightness levels. Photographic copies of compared pictures are included in the report. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1971
- Accession Number
- AD0730679
Entities
People
- Bernard Lippel
Organizations
- United States Army Communications-Electronics Command